The present invention relates to a laser instrument and also relates to a method for adjusting the laser power of a laser beam.
Laser instruments that generate point-shaped and/or line-shaped laser beams are known for performing leveling or marking work in interior and exterior construction. The laser beams are used to transfer reference points or reference lines onto walls, ceilings and floors. A distinction is made in terms of these laser instruments between rotary laser instruments, which generate a line-shaped laser beam by rotating a laser beam source or beam-deflecting optics around an axis of rotation, and point and/or line laser instruments, which generate point and/or line-shaped laser beams by means of beam-forming optics such as cylindrical lenses and prisms.
Known rotary laser instruments are operated in a first operating mode, the rotation mode, a second operating mode, the line mode, and/or a third operating mode, the point mode. In rotation mode, the laser beam is moved at a constant rotation speed around the axis of rotation. In line mode, the laser beam is moved back and forth in a limited angle range between a first and second end point and in point mode the laser beam rests, i.e., the rotation speed becomes zero.
The maximal permissible laser power is limited in the case of laser instruments that may be operated without protective measures such as safety goggles. The human eye is protected by the optico-facial winking reflex in the event of accidentally looking into the laser beam momentarily. The maximum permissible laser power is dependent on the operating mode in which the laser instrument is being operated. In rotation mode, the laser beam rotates at a constant rotation speed around the axis of rotation and the laser beam meets the human eye only momentarily. In line mode, there is a deceleration and acceleration of the laser beam in the region of the end points, wherein the laser beam rests at the end points. If the laser beam meets the human eye in the region of the end points, the portion of the laser beam that is absorbed by the eye is greater and the risk of damage increases.
German Patent Document No. DE 44 21 073 discloses a known rotary laser instrument, which is operated in a rotation mode and a point mode. The laser power of the laser beam is adjusted as a function of the rotational speed of the rotating optics. No line mode is provided in DE 44 21 073.
A further problem of known rotary laser instruments which are operated in line mode is that the laser line gets fuzzy in the region of the end points. The fuzziness of the laser line arises from the deceleration and subsequent acceleration of the laser device by the motor unit.
It would be desirable to improve a laser instrument and a method for adjusting the laser power with regard to the disadvantages explained above. In contrast, the object of the present invention is making a laser instrument available in which the laser beam is as well visible as possible in line mode and the risk of damage to the user is reduced. In addition, the laser line is delineated as precisely and sharply as possible.
This object is attained with the laser instrument according to the invention and with the method for adjusting the laser power of a laser beam.
According to the invention, a control device is provided for the laser instrument, which adjusts the laser power of the laser beam as a function of a rotation angle and/or an angular velocity of the rotating device. Adjusting the laser power as a function of the rotation angle or the angular velocity of the rotating device makes it possible to utilize the maximum available laser power of the laser device in an optimal manner and simultaneously reduce the risk of damage to the user's eye.
A measuring device is preferably provided which determines the rotation angle of the rotating device around the axis of rotation, wherein the measuring device is especially preferably configured as an encoder device with a locking disk having locking elements, and a photo interrupter, wherein the locking disk is connected to the rotating device in a rotationally fixed manner. In this way, the locking disk can be connected in a fixed manner to a rotatable shaft or be connected to the rotatable shaft in a rotationally fixed manner via gearwheels or belts. The advantage of a locking disk with a fixed connection is that measurement of the rotation angle is stable from outside influences, above all, temperature. Interconnecting a transmission ratio allows the resolution of the rotation angle to be increased.
In a preferred embodiment, a second measuring device is provided, which determines the angular velocity of the rotating device around the axis of rotation. In this case, the second measuring device especially preferably determines the angular velocity from the rotation angle of the first measuring device and a time, which is recorded by a timing device.
According to the invention, the method for adjusting the laser power provides that the laser power of the laser beam is adjusted as a function of a rotation angle and/or an angular velocity of the rotating device.
In a first preferred method variant, the laser power of the laser beam is reduced to zero when falling short of a first rotation angle, which corresponds to the first end point of the laser line, and/or when exceeding a second rotation angle, which corresponds to the second end point of the laser line. In doing so, the rotating device is especially preferably decelerated or accelerated in a first angle range between the first end point of the laser line and the first turning point and/or in a second angle range between the second end point of the laser line and the second turning point. Due to the fact that the deceleration and acceleration of the rotating device take place outside of the laser line, the laser beam within the laser line can be emitted with maximum laser power. Rapidly switching the laser power from a maximum laser power to zero produces a sharply delimited laser line between the first and second end points.
In a second preferred method variant, the laser power of the laser beam decreases from a first power value to a lower second power value when falling short of a preset first angular velocity of the rotating device and/or increases from the second power value to the first power value when exceeding a preset second angular velocity of the rotating device. The laser power of the laser beam especially preferably changes continuously or rapidly from the first power value to the second power value.
Exemplary embodiments of the invention are described in the following on the basis of the drawings. These drawings are not necessarily supposed to represent the exemplary embodiments to scale, rather the drawings are executed in a schematic or slightly distorted form when it is useful for explanatory purposes. Reference is made to the pertinent prior art with respect to additions to the teachings directly identifiable from the drawings. It must be taken into consideration in this case that a wide range of modifications and changes related to the form and detail of an embodiment can be undertaken without deviating from the general idea of the invention. The features of the invention disclosed in the description, the drawings as well as in the claims may be essential for the further development of the invention both separately as well as in any combination. Moreover, all combinations of at least two features disclosed in the description, the drawings and/or the claims fall within the scope of the invention. The general idea of the invention is not restricted to the exact form or detail of the preferred embodiment described and depicted in the following or restricted to a subject matter, which would be limited as compared to the subject matter claimed in the claims. In the case of any dimensioning ranges given, values within the stated limits are also meant to be disclosed as limit values, and be applicable at will and claimable. For the sake of simplicity, the same reference numbers are used in the following for identical or similar parts having an identical or similar function.
Additional advantages, features and details of the invention are disclosed in the following description of the preferred exemplary embodiments as well as on the basis of the drawings.